Hearing aids are portable hearing devices provided to people with impaired hearing. In order to accommodate the numerous individual requirements, different designs of hearing aids are provided, such as, for example, behind-the-ear-hearing aids (BTEs), in-the-ear-hearing aids (ITEs) and concha-hearing aids. The hearing aids described by way of example are worn on the outer ear or in the auditory canal. In addition, also available on the market are bone conduction hearing aids, implantable or vibrotactile hearing aids. In such cases, the damaged hearing is stimulated either mechanically or electrically.
In principle, hearing aids have the following essential components: an input transducer, an amplifier and an output transducer. The input transducer is generally a sound pickup, for example a microphone, and/or an electromagnetic receiver, for example an induction coil. The output transducer is generally implemented as an electroacoustic transducer, for example a miniature loudspeaker, or as an electromechanical transducer, for example a bone conduction hearing aid. The amplifier is usually integrated in a signal processing unit. This basic structure is shown in FIG. 1 using the example of a behind-the-ear hearing aid. One or more microphones 2 to pick up the sound from the environment are integrated in a hearing aid housing 1 for wearing behind the ear. A signal processing unit 3, which is also integrated in the hearing aid housing 1 processes and amplifies the microphone signals. The output signal from the signal processing unit 3 is transmitted to a loud speaker or receiver 4, which issues an acoustic signal. The sound may optionally be transmitted via an acoustic tube, which is fixed in the auditory canal with an otoplastic, to the eardrum of the person wearing the device. The power supply for the hearing aid and in particular for the signal processing unit 3 is provided by a battery 5 which is also integrated in the hearing aid housing 1.